A medical mystery that had a family believing their toddler might have a brain tumor, or worse, was finally solved by using new technology at Duke University Medical Center.

Best of all, treatment for the child’s loss of muscle control turned out to be in the form of a vitamin.

Just days before starting chemotherapy for a presumed autoimmune disorder, two-year-old Cara Greene was taken to Dr. Vandana Shashi, a geneticist who was able to pinpoint a rare genetic disorder that would effectively respond to high doses of Vitamin B2.

(WATCH the video above or READ the story from CBS *NOTE Auto-playing ads, so adjust your speakers)